Low-voltage low-power variable gain amplifier

Abstract

In high speed communication applications, e.g., optical communication, a variable gain amplifier is used for input signal amplitude normalization or for linear equalization. Traditionally a bipolar Gilbert multiplier circuit is used. When moving towards a low-power application, a modified circuit topology is implemented to reduce the minimum supply voltage requirement of the variable gain amplifier while ensuring that bias current levels remain substantially the same and achieving the same current switching capacity as the traditional circuit. As a result, the power consumption of the circuit can be greatly reduced. The modified circuit topology combines the amplifier and gain transistors and achieves gain programming using a voltage difference of two pairs of floating voltage sources.

Description

TECHNICAL FIELD OF THE DISCLOSURE[0001]The present invention relates to the field of integrated circuits, in particular to low-voltage low-power variable gain amplifier.BACKGROUND[0002]Electronics are made up of integrated circuits. Integrated circuits process signals and perform a myriad of functions. Analog circuitry is a group of circuits which processes signals in analog form (i.e., continuous, variable signals). One common analog circuit is the variable gain amplifier. The variable gain amplifier is a circuit which amplifies an input signal based on a gain coefficient. The gain coefficient can be varied or adjusted according to a control voltage. The variable gain amplifier is found in many audio applications and optical communications applications. Even though there are many well-established circuit topologies for the variable gain amplifier, ever-changing requirements imposed on the variable gain amplifier continue to make it difficult to design and implement a variable gain ...

AI Technical Summary

Benefits of technology

The patent presents a modified circuit topology for a variable gain amplifier used in high-speed communication applications such as optical communication. This modified circuit reduces the minimum power required for the amplifier while maintaining the same bias current levels and achieving the same current switching capacity as the traditional circuit. This results in a significant reduction in power consumption. The modified circuit utilizes a combination of amplifier and gain transistors, and achieves gain programming using a voltage difference of two pairs of floating voltage sources.

Problems solved by technology

Even though there are many well-established circuit topologies for the variable gain amplifier, ever-changing requirements imposed on the variable gain amplifier continue to make it difficult to design and implement a variable gain amplifier.

Images